html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/5329#issuecomment-1254067180,https://api.github.com/repos/pydata/xarray/issues/5329,1254067180,IC_kwDOAMm_X85Kv4vs,465045,2022-09-21T18:19:57Z,2022-09-21T18:19:57Z,NONE,"I just accidentally tried to open `myfile.h5.h5` (I meant to open `myfile.h5`) and was confused about the `ValueError`.

- Should `.h5` be added to the list of extensions that map to the NetCDF engine?
- Could the error message for the `ValueError` (or any of the alternate exception classes discussed above) include text suggesting that an incorrect file path (or other URL?) could be the culprit?","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843895606,https://api.github.com/repos/pydata/xarray/issues/5329,843895606,MDEyOklzc3VlQ29tbWVudDg0Mzg5NTYwNg==,9010180,2021-05-19T08:54:57Z,2021-05-19T08:54:57Z,NONE,"> I think it is OK to add a dedicated `xarray.EngineGuessingError`, but I'd not try anything more complex and in general invite users to pass `engine` explicitly.

I'm reluctantly inclined to agree. (But ""reluctantly"" only because this means that we may have a lot of xcube code to check and update now.) If the engine is explicitly specified, the question of which exceptions to expect becomes a lot easier to handle, since it's now just between the caller and the engine.

Probably the `open_dataset` documentation should actively discourage reliance on engine guessing for anything but interactive use, and point out that callers need to check the documentation for the selected engine to determine which exceptions (other than `EngineGuessingError`) might be thrown.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843824599,https://api.github.com/repos/pydata/xarray/issues/5329,843824599,MDEyOklzc3VlQ29tbWVudDg0MzgyNDU5OQ==,226037,2021-05-19T07:28:03Z,2021-05-19T07:28:03Z,MEMBER,"@shoyer and @pont-us my take is that `engine=None` is mostly and feature to help new users experiment with xarray. The logic for autodetecting the engine has always been extremely fragile and the result depends on what packages are installed on the system.

I think it is OK to add a dedicated `xarray.EngineGuessingError`, but I'd not try anything more complex and in general invite users to pass `engine` explicitly.

Examples of strings that identify a dataset when the right backend is installed, but are not paths and the `FileNotFoundError ` would sound confusing:
- `/vsizip/my.zip/my.tif` with `rioxarray`
- `https://myhost/myfile.nc` with `netcdf4` and others","{""total_count"": 1, ""+1"": 1, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843757305,https://api.github.com/repos/pydata/xarray/issues/5329,843757305,MDEyOklzc3VlQ29tbWVudDg0Mzc1NzMwNQ==,1217238,2021-05-19T05:28:04Z,2021-05-19T05:28:04Z,MEMBER,"Actually, thinking about this a little more, you should get `NoMatchingEngineError` if you try to open a text file with Xarray.

But if you pass in a local filesystem path and try to open an entirely non-existent file, then `FileNotFoundError` would be appropriate.

In theory, one could write an `open_dataset` backend that interprets a local path in an arbitrary way, but that is not the intent of `open_dataset`, which is intended to handle things like files/directories, other URIs and file contents. If you want to interpret strings very differently you should write a new function for opening.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843752655,https://api.github.com/repos/pydata/xarray/issues/5329,843752655,MDEyOklzc3VlQ29tbWVudDg0Mzc1MjY1NQ==,1217238,2021-05-19T05:15:39Z,2021-05-19T05:15:39Z,MEMBER,"Ouch! I agree this is annoying. And yes, the open_dataset docs definitely need updating. 

The general rule is that `ValueError` is too generic of an exception for it to be appropriate to catch in user code. So indeed, if you need to catch that error something has gone wrong :).

Given this use case, perhaps we should have a special exception type here, something like `xarray.NoMatchingEngineError`.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843138842,https://api.github.com/repos/pydata/xarray/issues/5329,843138842,MDEyOklzc3VlQ29tbWVudDg0MzEzODg0Mg==,9010180,2021-05-18T12:43:55Z,2021-05-18T13:40:41Z,NONE,"@aurghs Point taken, but in that case the `xarray.open_dataset` documentation probably needs updating: currently it says ‘Strings and Path objects are interpreted as a path to a netCDF file or an OpenDAP URL and opened with python-netCDF4, unless the filename ends with .gz…’. In particular I find the behaviour with `Path` confusing: this type is unambiguously a filesystem path, but still results in a `ValueError` rather than `FileNotFoundError`. And in Python 3, `str` and `bytes` are distinct (though I suppose a `str` might still be a URL rather than a file).

In principle, though, I'd be OK with any selection of potential exceptions, as long as they're documented. The current practical problem for us (the xcube developers) is that the behaviour change from 0.17 to 0.18 means that we now have to audit our existing codebases for potential uncaught `ValueError`s.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843101733,https://api.github.com/repos/pydata/xarray/issues/5329,843101733,MDEyOklzc3VlQ29tbWVudDg0MzEwMTczMw==,35919497,2021-05-18T11:48:37Z,2021-05-18T12:24:21Z,COLLABORATOR,"I think that It's not a bug: `filename_or_obj` in `open_dataset` can be a file, file-like, bytes, URL. The accepted inputs depend on the engine.  So it doesn't make sense to raise a `FileNotFoundError` if the engine is not defined by the user or not automatically detected by xarray.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618
https://github.com/pydata/xarray/issues/5329#issuecomment-843032959,https://api.github.com/repos/pydata/xarray/issues/5329,843032959,MDEyOklzc3VlQ29tbWVudDg0MzAzMjk1OQ==,10194086,2021-05-18T09:59:51Z,2021-05-18T09:59:51Z,MEMBER,Thanks for the report - I added that to the list of todos for the 0.18.1 patch release.,"{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,894125618